The cheapest and easiest no maintenance biofilter you can ever make

JohnHuff

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This is what I have for my pond right now. A biofilter doesn't have to be store bought, be very complicated or cost a lot of money. It only has to have 3 things: have good water flow, lots of surface area and lots of air.

Mine just has 2 components: a bucket and bioballs but it fulfills all the requirements of a good biofilter.

1) A container: just a 5 gallon bucket from Lowes. I've left it outside in freezing temperatures and it hasn't cracked yet. I think the Sun is probably more damaging but it's more or less covered from the sun.

yoFKc6e.jpg


2) Bioballs: These are cheap and you can get them from ebay, aliexpress or Amazon.
42L8PyD.jpg


3) So what I do is drill a large hole about 3/4 of the way up and insert a pipe. The pipe is the outlet and drains back into the pond. I fill the bucket with water and then throw in the bioballs. The amount of bioballs determine your filtration capacity because it's the surface area of the bioballs that holds the beneficial bacteria. You can use any kind of floating media.

4) Water from the pond is pumped to the top of the bucket. I angle the incoming water so that it creates a swirl and splashes into the bucket. That does two things: it creates movement of the bioballs and the entry of the water creates a lot of bubbles. I at first thought I should put in an airstone at the bottom of the bucket but I think the splashing of the water aerates it enough.

Cons:
1) A 5g bucket isn't going to work for big ponds but it's good enough for my 700g pond with about 20 small fish in it. You could use a bigger container and more balls for a bigger pond.
2) There's a limit to how many bioballs you can have in the bucket. Too many and the bioballs won't get enough circulation. They'll just bunch up or don't move enough. Too little and there isn't enough surface area, but a 5g bucket holds quite a lot. And you can throw in media of a different shape so they mix better. RIght now I have more than a gallon's worth of balls and they move around quite well.

Pros:
1) No maintenance is needed, the bioballs don't get clogged up. When it gets too cold, I switch the main pump off and I rinse everything out at the beginning of the next season when I restart it.
2) The bucket of bioballs is a moving bed filter and provides the 3 things that a biofilter needs: good circulation from the water splashing in so the N compounds can get to the bacteria, good aeration because of the bubbles for the aerobic bacteria and lots of surface area for lots of bacteria,

What this isn't and doesn't have is mechanical filtration. I have both pre and post pump filter pads/mats for that. I used to only have pre-pump filter pads but I found that solids would still get through so now I have filter pads that also catch solids from the outlet. But the water that goes in the bucket is clean enough that it doesn't clog up the bioballs.

In essence this bucket is just the bio-filtration part of the system. You can add buckets before and/or after with settling tanks or filter pads or even more bioballs. You can go crazy and create a wastewater type of system. My current setup is just a dollar store version of this with the centerpiece and filter pads before and after the bucket.
uOQLU3a.jpg


My pet peeve is being forced to clean the filter pads to the pump when those get clogged up. And I have to do that because clogged pads hurt the pump (I can't remember if clogged water inflow or outflow hurts the pump more). So every time when I notice the water flow decrease I have to rinse out the pads and I have to do that very frequently during the active season (and not at all during winter).

But eventually (maybe next season), I'm going to alter the pathway of the water so that I won't need to change the filter pads until I want to.
 
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you must know something I don't the last time I bought bio balls they were hardly cheap. the plastic shaved strips I would see as efficient and a hole lot cheaper.
 

JohnHuff

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JohnHuff

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interesting they are completely different from the dupla bio balls I used once upon a time

Yea, my bioballs are a few years old and from looking at the website, it seems there are many types of bioballs now. I'm not sure what I feel about the foam inside. If the influent water is even slightly dirty, solids will get trapped in the foam and it doesn't look like it can ever get cleaned out.
 

JohnHuff

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These are the pads from that link:
143978.JPG

According to that website they are $8.18 for 20, which is not cheaper than the bioballs I referenced earlier and I don't recommend pads like these because once the outside gets clogged up, the insides will be useless. Instead, I recommend these for mechanical filtration.
 
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I'm not sure what I feel about the foam inside. If the influent water is even slightly dirty, solids will get trapped in the foam and it doesn't look like it can ever get cleaned out.
I agree the foam would likely get clogged up, be a pain to clean, and defeat the whole idea of having a moving bed bio-filter.
I use Kaldness media in my moving bed bio-filter. It stays very clean with the type of circulation I have in the tank.
Kaldness type media
 

JohnHuff

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These are the balls in question:

0pT6S2g.jpg


and I ordered a bunch of them because they were so cheap just to check them out!
 

popeye46

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These are the pads from that link:
143978.JPG
the items pictured are made of the same material that skippy sells which are just cut up scrubber pads. the price on the web site is only $5.34 for 20 but I took your advice and ordered 200 bio balls, I hope they work.
According to that website they are $8.18 for 20, which is not cheaper than the bioballs I referenced earlier and I don't recommend pads like these because once the outside gets clogged up, the insides will be useless. Instead, I recommend these for mechanical filtration.
 
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I think the point of the foam in the balls is for benificial bacteria to colonize. The porous foam has a huge internal surface area for a vigorous population of bacteria to breakdown biological waste. It isn't meant to filter anything, bio balls support the biome that reduces nitrates from fish waste. At least, that is how bio balls work in aquarium filtration. Prefilter material that can be rinsed or replaced is meant to keep the bio balls from being buried in particulate matter and allow the beneficial bacteria to flourish and water to flow around them constantly. I have also used mesh bags of hydroballs (porous clay balls) instead of bio balls, so I could remove the bags and rinse them ocassionally.
 
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I use plastic fencing in a 275 gallon tank. I think I paid $6 dollars for a 50 foot roll and I have two rolls in it. For the mechanical part, I have malata pads on the bottom. The filter is big enough that I only clean it in the fall.
 
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Great economical way of getting it done! I like saving money via DIY projects.
You have the water splashing into the top of the bucket.
Would it be better if the water entered towards the bottom of the bucket (bulkhead fitting) and worked it's way up through the bio balls and out the upper outlet pipe? You can even snap the lid on the bucket.
I don't mean to criticize, just suggesting....
 

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